Electronic door lock key re-sequencing function
First Claim
1. An electronic security device openable in response to a release signal, said device comprising:
- (a) a key means having at least a first combination and first and second calculation data stored thereon;
(b) lock memory means for storing a lock combination;
(c) key reading means for receiving said key means, and for reading from said key means said first combination and said first and second calculation data; and
(d) electronic logic means coupled to said lock memory means and said key reading means for;
(1) comparing said first combination read from said key means with said lock combination received from said lock memory means;
(2) calculating a second combination from said first combination and said first calculation data read from said key means, and comparing said second combination with said lock combination;
(3) calculating a third combination from said second combination calculated by said logic means and said second calculation data read from said key means, and comparing said third combination with said lock combination; and
(4) generating said release signal in response to a match between said lock combination and one of said first, second and third combinations.
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Abstract
An electronic security device has at least one lock and a control center for generating keys to the lock. When a new key is generated, a new (second) combination is generated by applying a predetermined algorithm and randomly generated (first) calculation data to the previous (first) combination. To calculate a next new (third) combination, another randomly generated (second) calculation data is applied to the second combination using the same algorithm. The control center stores, on the key, the third combination, and the second calculation data used to obtain it and the first calculation data used to obtain the second combination. At the lock, the third combination is compared with a stored combination and if there is no match, the lock calculates a possible second combination by applying an algorithm, which is the inverse of the predetermined algorithm, to the stored combination using the second calculation data read from the key. If there is still no match, the lock calculates a possible first combination using the first calculation data read from the key. If there is still no match, the lock will not be opened. In another embodiment of the invention, a check-in time and a check-out time are provided on the key, and the lock will not open unless the time is between the check-in and check-out time when the key is inserted.
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Citations
41 Claims
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1. An electronic security device openable in response to a release signal, said device comprising:
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(a) a key means having at least a first combination and first and second calculation data stored thereon; (b) lock memory means for storing a lock combination; (c) key reading means for receiving said key means, and for reading from said key means said first combination and said first and second calculation data; and (d) electronic logic means coupled to said lock memory means and said key reading means for; (1) comparing said first combination read from said key means with said lock combination received from said lock memory means; (2) calculating a second combination from said first combination and said first calculation data read from said key means, and comparing said second combination with said lock combination; (3) calculating a third combination from said second combination calculated by said logic means and said second calculation data read from said key means, and comparing said third combination with said lock combination; and (4) generating said release signal in response to a match between said lock combination and one of said first, second and third combinations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An electronic security system comprising:
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(a) a control center including; (1) means for generating first and second calculation data; (2) means for generating first, second and third combinations, said second combination being generated by applying a predetermined algorithm to said first combination and said first calculation data, and said third combination being generated by applying said predetermined algorithm to said second combination and said second calculation data; (3) means for storing said third combination and said first and second calculation data on a key (b) a security device openable in response to a release signal, said security device including; (1) memory means for storing a lock combination; (2) key reading means for reading said third combination and said first and second calculation data from said key; and (3) electronic logic means for; comparing said third combination with said lock combination; calculating said second combination from said third combination and said first calculation data, and comparing said second combination with said lock combination; calculating said first combination from said second combination and said second calculation data, and comparing said first combination with said lock combination; and generating said release signal in response to a match between said lock combination and one of said first, second and third combinations. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of operating an electronic security device having a lock combination stored in said device, said method comprising the steps of:
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generating first calculation data; storing said first calculation code and determining. from said first calculation data and a first combination, a second combination; generating second calculation data; storing said second calculation code and determining. from said second calculation data and said second combination, a third combination; comparing said third combination with said lock combination; calculating said second combination from said third combination and said second calculation data, and comparing said second combination with said lock combination; calculating said first combination from said second combination and said first calculation data, and comparing said first combination with said lock combination; and unlocking said security device in response to a match between said lock combination and one of said first, second and third combinations. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. An electronic security system comprising:
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a control center including; first means for determining a first combination; second means for determining first and second predetermined times measured from an initial time; and key making means connected to said first and second determining means for storing said first combination and said first and second predetermined times on a key, and a security device, openable in response to a release signal, including; reading means for reading said first combination and said first and second predetermined times from said key; memory means for storing a second combination; means for determining an elapsed time from said initial time; circuit means connected to said memory means, said reading means and said means for determining and including means for comparing said first combination read from said key with said second combination obtained from said memory means and said elapsed time obtained from said means for determining with said first and second predetermined times read from said key, and means for issuing said release signal when said first and second combinations correspond and said elapsed time is greater than or equal to said first predetermined time and less than or equal to said second predetermined time, said means for issuing being non-responsive when said elapsed time is less than said first predetermined time and greater than said second predetermined time even if said first and second combinations are correspond.
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36. In an electrically programmable security system of the type wherein the lock is reprogrammed by inserting into the lock a key having information thereon relating to the old combination and a new combination, the improvement comprising,
means for adding to said key information relating to the combination of said lock prior to said old combination, and means in said lock for calculating, from information on said key, said old combination and said prior combination.
Specification